With corrections for prevailing era conditions, a dead heat between Walter Johnson and Lefty Grove--check out Grove's neutralized stats at
www.baseball-reference.com. Put him in the National League in 1966, playing at Dodger Statdium, and virtually every one of his seasons looks as good or better than Koufax circa 1965-1966. Remember, Lefty pitched when the entire league hit .280 plus, and a good number of the stadiums were of the bandbox variety.
Nice thread,
Larry